Method of underpinning and supporting walls.



, T. K. THOMSON. METHOD 0F UNDBRPINNING AND SUPPORTING W ALLs.

APPLICATION FILED 00T. 22, 1908.

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T. K. THOMSON.

METHOD 0F UNDERPINNING AND SUPPORTING WALLS. APPLICATION FILED 00T. 22, 1908. 9 1 8, 1 00 Patented Apr. 13, 1909L 2 SHEETS-SHEET 2.l

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nUNTFD STATES PATENT OFFlQFi.

THOMAS KENNARD THOMSON, OF 'YONKERS, NEW YORK.

METHOD OF UNDERFINNIN G lANI) SUPPORTING- WALLS.

To all whom it' may concern:

Be it known that l, THOMAS KENNARD THOMSON, a citizen of the YUnited States, and a resident of the city of Yonkers, in the county of 'Westchester and State of New York, have invented certain new and useful Improvements in Methods of Underpinning and Supporting Walls, of which the following is a specification, reference being had to the accompanying drawings, forming a part hereof.

lt frequently happens, under conditions of modern building operations, that a contractor is called upon to provide an underpinning or sub-foundation for buildings adjacent to those he is about to erect and either before or coincident with the erection of the new structures. There are also instances where buildings have been erected upon foundations which are imperfect or insecure and which therefore require a more substantial underpinning aside from any considerations arising out of proximate excavations. To meet this necessity of providing such underpinning, particularly in cases where atemporary shoring only is required, it is desirable that a method be pursued which shall involve a minimum of expense upon the part of the contractor.

The method which is provided in accordance with the present invention is designed to reduce the expense of such operations as practiced heretofore, by economizing the time and labor required in effecting the underpinning and by being able to employ less expensive materials in carrying out the operations.

Another object of the invention is to provide a method of underpinning which may be practiced without annoying the tenants of the building being underpinned such as would be occasioned by shocks incident to the und erpinning.

The improved method will be described in full hereinafter in connection with the accompanying drawings in which,

Figures l to 7 inclusive are illustrations in vertical section of successive steps in the imiroved method, such figures showing the building of a shaft in segments and sections. Fig. 8 is a plan view of one of the segments, showing a key section forming a part of the segment, Fig. 9 is a view partly in side elevation and partly in section of a wall which has Y'been underpinned in accordance with the Specification of Letters Patent.

Application led. October 22, 1908.

Patented April 13, 1909.

Serial No. 458,936.

improved method, some parts of the figure being broken away for more complete illustration, and Fig. l() is a detail plan view looking down from the plane indicated by the line l0-10 in Fig. 9.

The present method 'of underpinning involves the building of one or more vertical shafts underneath or adjacent tothe wall to be underpinned, the particular number of shafts depending upon the extent of the wall and the nature of the underpinning to be provided. ln accordance with the invention herein, these shafts are sunk by excavating always in advance of the shaft until the latter has been completed and by adding successive segments thereto one in advance of the other until the last segment has reached hard pan or some suitable base, or until the shaft has reached a sufficient length. The initial step in the method is the preparation of a space for locating the top segment of the shaft. The precise nature of this step will vary in accordance with the particular conditions which are met with in the wall to be underpinned. lf this wall has its foundations very near the surface of the ground, it will be sufficient to dig a hole underneath the wall big enough to admit the tcp segment of the shaft. lf, on the other hand, the wall extends considerably below the surface, it may be preferable to cut a hole in the wall just below the surface of the ground and to insert the top segment of the shaft in the hole thus prepared. lf again the grillage beams are very low and considerably below the surface, it may be preferable to sink shafts upon each side of the wall in which case the top segments of the shafts to be built are located in holes provided one on each side of the wall. lt will be seen therefore that while the precise operations in locatinOr the top segment of the shaft may be varied to meet different conditions, still the character of the Erst step of the method, Vin so far as it involves the providing of a hole to contain the top segment, always remains the same.

ln Fig. 9, where a typical instance of underpinning in accordance with the improved method is illustrated, the wall above one of the vertical shafts will be seen to be broken away, thus affording an opening or hole through which the top segment may be introduced. ln this particular case, the top segment a has been introduced through the o ening in the wall and has been located in t e ground just below the opening. Farther along to the right in said figure where the grillage beams l) will be seen to be somewhat lower, the top segments a of the shafts are located in the ground upon each side (Fig. 10) of the wall. These top segments a maybe either integral rings or they may be formed in sections. If formed in sections the sections are preferably united to form a complete ring before the segment is placed in position, that is if conditions will permit the passing ofl the complete segment into the opening prepared for it in its assembled state. The material of which the segment, and of course the entire shaft, is composed may be either metal, wood, or any substance whatever which is capable of' retaining its shape during the building of the shaft. Obviously too, the segment and the shaft may be otherwise than cylindrical as shown, that is, it maybe made square or rectangular or in any other suitable shape.

When the top segment has been located in position, the space between the segment and the sides of the hole in which it has been inserted are filled with earth or concrete or any suitable material which is packed or rammed down rather tightly. The purpose of such backdilling is to fasten the segment from vertical displacement.` It will be seen hereinafter that the lower segments of the shaft are fastened to the top segment so that it is particularly desirable that the top segment e secure in its position in order that no displacement shall occur. It may be that the dimensions of the hole will be such that the top segment will be fitted tightly therein in the first instance so as to be held from displacement by skin-friction, in which case no ack-filling will be required. In the present case the back-filling is indicated inthe drawings by the lettere, and where the hole for the top segment is cut in the wall, such backe filling between the sides of the wall'v and the top segment will preferably consist of concrete or cement or some other suitable substance adapted. to unite the top segment to the wall.

After the top segment has been fastened in position, the excavation is carried beneath the top segment and in such a manner as to provide a space for a section of the adjacent segment, such excavation being indicated at d in Fig 3. This is effected by a workman who excavates within the top segment, the earth being removed in any suitable manner, as by a tackle and bucket, compressed air being used wherever water is encountered. When the excavation is finished for a portion of the next segment, the corresponding section f of the segment is introduced through the top segment and is securedk in Vosition by means o angle plates e. Then te excavation is continued until.

it is sufficient to admit another section of the .segment which is introduced through the top section and secured thereto in like manner. ln this way each succeeding segment is excavated for and added to the preceding segment. In order that the sections of each segment may be carefully fitted to each other in assembling the sections as just described, each segment may be provided with what is known as a key or a key-section k in which the edges are tapered, as illustrated in Fig. 8, instead of being precisely radial, as they might be if the segments were inserted in their assembled state. lt will be easily un* derstood without further explanation, how such a provision enables the more accurate fitting of thei several sections. VThis keysection is preferably made relatively narrow as shown in the figure.

In Fig. 7 the fourth segment is shown as having a space g at one side thereof, which space might be encountered in excavating or might be formedby the excavator. Such space may be filled with grout, dirt or Vany other soft material introduced through an opening 7L which may be formed in the side of the segment. Such an opening, however, may not require filling up, but it will be understood that, as a general rule, there should be little space left between the sides of the shaft and the inclosing earth in order that the skin-friction upon the several segments shall assist in holding them in proper vertical position, or to prevent the surrounding material from caving in.

When the shaft has been completed, it will generally be filled up with concrete or some other suitable material and the top of the shaft will be united with the superimposed wall, thus forming a supporting pillar extending down from the wall to whatever base it rests upon. As shown in Fig. 9, the wall is sup orted by a plurality of such pillars extem ing from one end to the other. At the far right in said figure and in Fig. 10, the pillars are shown as connected to the wall by cross beams i which support the grillage beams b.

lf it is desired to underpin an entire wall the shafts may be made square or rectangular and. sunk at intervals and then other shafts sunk in between them until a continuous wall is thus formed under the old wall. ln such a case the shell of each shaft may be left in or removed so as to allow the concrete, or whatever the shafts are filled with, to become continuous. In fact, in many places, if desired, the steel, wood or other cylinders or shafts may be removed from the bottom up, as the concrete brick-work, masonry or other filling is put in place thus saving the expensive lining for further use and allowing the concreting to come in direct contact withthe material in which the excavation has been made. Of course, there are some materials in which it would not be desirable to remove the shell or lining.

In order that the several steps of the improved method may be the more readily apreciated, Figs. 1 to 7 of the drawings have een provided to show these steps seriatim. Fig. 1 illustrates the hole in the ground. Fig. 2 illustrates the top segment located and the back-filling interposed between this segment and the walls of the hole. Fig. 3 illustrates the excavation for the first section of the second segment and Fig. d illustrates the first section (indicated by the letter f) of the second segment in position. 5 illustrates the second segment in position complete and Figs. 6 and 7 show the application of the same steps to the locating of the third and fourth segments. l of these figures, as well as Fig. 9, show the sections of one segment overlapping the sections of the adjacent segments. This arrangement of overlapping sections is obviously preferable, although not necessarily essential and may be departed from Without departing from the spirit of the invention.

Various other modifications and changes, both in the embodiment of the method and of the materials employed in carrying it out, may be made without departing from the spirit thereof.

Such a method of underpinning is obviously an expeditious one. Moreover, it may be carried out with comparatively small expense so far as cost of materials is concerned. This is due largely to the fact that the material of the segments or rings employed in building the shaft is not required to be of particularly great strength, such as would necessarily be the case where these segments are jacked or otherwise forced down into the earth. Where steel segments are employed, it has been demonstrated in actual practice that their thickness in a shaft four feet in diameter need not be over three-sixteenths of an inch. This fact alone greatly reduces the cost of construction. Besides this, the workman in ordinaryl cases requires very little beyond a scoop and a pail to eect the excavation. The method is therefore a particularly economical one. It should be noted that while it may be preferable to fill the cylinders or shafts in most cases with concrete, obviously they may be -filled with brick-work, masonry `or even packed well with sand or ashes.

I claim as my invention:

pinning, which consists in excavating in proximity to the wall to be underpinned to form a hole for the top segment of a vertical shaft, locating such top segment, excavating below the top segment, introducing successive segments through the top segment until the. shaft is complete, and then filling up the shaft and uniting the top of the shaft to the Wall.

3. The herein-described method of underpinning, u'hich consists in excavating in proximity to the wall to be underpinned to form a hole for the top segment of a vertical shaft, locating such top segment, excavating below the top segment, introducing successive segments in sections through the top segment until the shaft is complete, and then filling up the shaft and uniting the top of the shaft to the wall.

4. The herein-described method of underpinning, which consists in excavating in proximity to the Wall to be underpinned to form a hole for the top segment of a vertical shaft, locating the top segment, excavating below the top segment, introducing successive segments through the top segment until the shaft is complete, :filling up the shaft, and then uniting the top of the shaft and wall.

5. The herein-described method of underpinning, Which consists in excavating in proximity to the wall to be underpinned to form the top segment of a vertical shaft, locating such top segment and back-filling between the top segment and the sides of the hole, excavating below the top segment, and introducing successive segments through the top segment.

6. The herein-described method of underpinning, which consists in building a vertical shaft underneath the wall to be underpinned by cutting a hole in the wall and locating the to 3 segment of the shaft therein, .excavating bellow the top segment, introducing successive segments through the to segment until the shaft is complete, and t en filling. the space between the top segment and the wall.

7. rlhe herein-described method of underpinning, which consists in cutting a hole in the wall to be underpinned, sinking a vertical shaft thereunder by inserting the top segment thereof in said hole, excavating below said top segment, adding in sections the successive segments until the shaft is complete then filling up the shaft, and uniting the top of the shaft to the wall.

8. The herein-described method of underpinning, which consists in cutting a hole underneath the wall, inserting the top segment of a shaft therein, back-filling around said segment, excavating below said segment, and adding successive segments thereto through the top segment until the shaft is complete. V

ico

9. The herein-described inethod of underpinning` Which consists in cuttingI :i hole underneath the Wall, insertinfr the top segment of a shaft therein, back-'filling around said segment, excavating beloW seid segment for a portion of the succeeding segment, adding said portion of the succeeding segment through the top segment, then excavating for another portion of said succeeding segmentJ and so on until the shaft is complete.

10. The herein-described method of underpinning, which consists in cutting a hole in proximity to the Wall to be underpinned, inserting the top segment of e shaft. therein7 back-filling around saidsegment, excavating below said segment 'for e portion of theVl s'u'poeeding segment, adding said portion of the succeeding segment through the top seginent, then excavating for another portion of the'suooeeding segment, and so on'until the shaft is complete, and finally connecting the top of the shaft and the Wall.

rlhis specification signed and witnessed this 14th day of October, 1908.

THGS. KENNARD THOMSN. Signed in the -resence of- LUCIUS VARNEY,

MCGRANN. 

